Number-chart.



NUMBER CHART.

(Application filed June 29, 1900.)

(No Model.)

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UNITED STATES PATENT Fries.

MATTIE F. DOOKERY, OF WIIITEWATER, \VISCONSIN.

NUMBER-CHART.-

SPECIFICATION forming" part of Letters Patent NO. 680,411, dated August13, 1901.

Application filed June 29, 1900. Serial No. 22,041. (No model.)

To all whom it may concern:

Be it known that I, MATTIE F. DOCKERY, a citizen of the United States,residing at Whitewater, in the county of Walworth and State ofWisconsin, have invented new and useful Improvements in Complete Number-Charts, of which the following is aspecification.

My invention relates to improvements in number-charts.

Herctofore charts have been employed illustrative of some one of thefundamental rules of arithmetic; butthese have been found objectionable,owing to the tendency of the pupils to memorize the various combinationsand their results.

The object of my invention is to provide a form of chart which will notbe merely illustrative, but which will contain a complete series ofinterchangeable digits for all the factors of a problem, whereby asingle chart may be manipulated to present a practically unlimitednumber of problems.

My invention also has for its object the provision of means whereby asingle chart may be used for teaching any one or all of the fourfundamental rules of arithmetic, together with means for increasing ordiminishing the numerical importance of the various factors or elementsof a problem, in accordance with the capacity of the pupil to make thecalculations presented.

In the following description reference is had to the accompanyingdrawings,inwhich Figure l is a view of a portion of one of my improvedcharts as arranged for the simplest problems. Figs. 2, 3, and 4 areViews of the respective number-slides. Figs. 5, 6, 7, and 8 are views ofportions of my improved chart, showing the same as used for teachingaddition, subtraction, multiplication, and division, respectively. Fig.9 is a detailed sectional View drawn longitudinally through the slidecovering the divisor shown in Fig. 8.

Like parts are identified by the same reference-letters throughout theseveral views.

The chart A is provided with parallel slots a a, near which are groupeda series of numbers, as shown in Fig. 1. A number-slide B, of cardboardor other suitable material, is inserted through the slots in such amanner as to cover the intervening space on the face of the chart, theremainder of the slide being covered by the chart.

In Fig. 1 I have shown series of numbers grouped in concentric circlesaround the slots and the exposed portion of the slide, and I have alsoprovided for indicating the nature of the operation to be performed bymeans of a sign-slide 0, upon which are printed the four signs ofaddition, subtraction, multiplication, and division, respectively. Thisslide is inserted through parallel slots and held in the same manner asthe slide B and with one of the signs exposed on the face of the chart.The construction shown in this figure is designed especially for thesimpler mathematical problems. In use the teacher points to a u umber inone of the circular groups around the exposed portion of the slide,whereupon it is understood by the pupil that such number is to be addedto, subtracted from, multiplied by, or divided by the central or exposedslide-number, and the nature of the operation to be performed isindicated by the slide O. For example, when the adjustment is asindicated in Fig. 1, if the number 10 is pointed out in either of thecircles it will be understood that such number is to be multiplied bythe number 6, which is exposed on the slide in the central portion ofthe chart. If, however, the slide 0 should be changed to expose theminus-sign, it would be understood that the number 6 was to besubtracted from the number 10. If the plus-sign is exposed,the 6 willbeadded, and if the division-sign is exposed the number 10 will be dividedby the number 6.

Figure 5 represents an addition-column in which the slots at a. arelocated, one on each side of the various numbers composing the column,so that by means of the slides all the digits may be shifted orreplaced. In Fig. 6 the slide may be similarly used to vary both theminuend and the subtrahend indefinitely, as is also the case with themultiplicand and multiplier in Fig. 7 and the dividend and di visor inFig. 8.

It will be understood that the arrangement shown in Fig. l is intendedfor the simpler problems of mental arithmetic. The arrangement shown inFigs. 5 and 8 may, however, be rendered as complex as desired.

By comparing the slide B (shown in Fig. 5)

with the slides 13, B, and B (shown in Figs. 2, 3, and 4) it will beobserved that they are of relatively-increasing numerical importancei.a, when the slide B is adjusted to the addition-column of Fig. 5 eachcolumn of digits will when added together amount to less than ten, therebeing nothing to carry from one column to the next. With the slide B,however, the pupil will be compelled to carry from units to tens, &c.;but at most points of adjustment the pupil will not be compelled tocarry twice in succession. Th us by increasing the "numerical value ofthe slides problems may be increased in complex- (iit-y in proportion tothe capacity of the stuent.

It will be observed that the various slides are-of a width adapted tocover but one of the numbers or horizontal rows of digits of the problemand that the slots at are located at each end of the number; also, thatthe slides contain a greater number of digits than are represented inany one number of the problem, whereby a lateral adjustment of any slidein the slots will effect a complete change in the problem, not only byintroducing a new digit, but by changing the relative position of allthe remaining digits of that number. I attach great importance to thisprovision of means for not only inserting and removing digits from amathematical problem, but for shifting the relative position of thedigits in the problem, whereby the number of changes in the problem isnot limited by the number of digits on the slide or the number ofslides, but is substantially unlimited in view of the fact that thedigits cannot only be removed and replaced, but shifted in position,thus rendering it impossible for the memory of the student to assistin'any manner at arriving at the solution ofv the problem.

It will of course be understood that itis not necessary that the chartsshould be provided with fixed numbers, as all of them may be madeadjustable, if desired.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is j 1. The combination with a chart providedwith a mathematical problem; of a series of number slides or carriers; aseries of digits on each of said slides or carriers; means for mountingsaid slides or carriers on said chart, in positions to separately coverindividual numbers of the problem; and means for adjusting said slideslaterally whereby digits may be removed, shifted, replaced, or added,and the character of the problem indefinitely altered... V

2. The combination with a chart provided with a mathematical problem; ofa series of number slides or carriers, and a series of digits on each ofsaid slides or carriers; said chart being provided with parallel slotsor openings at the respective ends of the various numbers of the problemadapted to permit the insertion of the slides with a portion exposed onthe face of the chart between the slots and a portion or portions of theslide concealed at one or both ends, whereby said slides may be adjustedlaterally to alter the character of the problem, both by shifting theposition of the exposed digits and 'introducing new digits.

3. The combination with a chart provided with a mathematical problem,and having parallel slots arranged in pairs, one at each end of eachnumber of the problem; and a series of slides adapted to be inserted insaid slots toseparately cover the numbers of the problem and providedwith a series of digits exceeding in number the digits of the numbersuch slide is designed to cover, whereby a lateral adjustment of theslide will introduce new elements into the number and rearrange, theremaining elements with reference to the other factors of the problem.

In testimony whereof I affix my signature in the presence of twowitnesses.

MATTIE F. DOCKERY.

In presence of T. M. BLACKMAN,

WILL M. OowLEs.

